The present invention relates to remote sensing of gaseous materials through multi-spectral analysis via satellite, aerial, or ground based platforms and, in particular, it is concerned about reducing the effects of background radiation introduced into the spectral data.
It is known that spectral signatures may be used to identify component constituents in gaseous bodies. It is also known that illuminations passing through a gas plume after being reflected or radiated from a background surface exhibit spectral imprints from both the surface and the plume, thereby blurring the distinct radiometric phenomena emanating solely from the gas plume. This complication exists in both passive and active spectral analysis methods as illustrated in FIGS. 1 through 3 at different wavelength-domains of the electromagnetic spectrum. Spectral and radiance data that has been estimated to emanate exclusively from the background may be used to evaluate correctly the gas plume spectral and radiance features. However, the un-obscured view of the background required to capture its data is frequently unavailable as illustrated in FIG. 4. The lack of a reliable method to obtain the data emanating exclusively from the background reduces the ability to properly identify and to accurately quantify the target gases. Therefore, there is a need for a method to obtain the required background spectral and radiance data in order to properly identify and quantity target species in a plume.